Starting device for electric motors.



H. M. SGHEIBE.

STARTING DEVI 0R ELECTRIC MOTORS. APPLIGATI LED SEP'I.9, 1907. 934,4Patented Sept. 21. 1909. SHEETSSHEET l.

WITNESSES t 9 a 70 v T ATTORNEY I H. M. SGHEIBE.

STARTING DEVICE FOR ELECTRIC MOTORS.

APPLICATION FILED SEPT. 9, 1907.

Patented Sept. 21,1909.

2 SHEETS-$HEET 2.

WITNESSES: {fit/$4,1-

UNITED sTArEs PATENT orrron.

mom) in. 'scnnrnn, or wrnxmsnune, PENNSYLVANIA, ASSIGNOR, BY innsnnASSIGNMENTS, TO WESTINGHOUSE ELECTRIC & MANUFACTURING COMPANY, or 'nAsrrrrrsnrme, rEnnsYLvANiA, A conronA'rron or PENNSYLVANIA.

STARTIL TG DEVICE FOR ELECTRIC MOTORS.

Specification of Letters Patent. Patented Sept. 21, 1909.

Application filed September 9, 1907. Serial No. 392,051. I

To all whom it may concern:

Be it known that I, HAROLD M. SGHEIBE, a citizen of the United States,and a resident of Wilkinsbur in the county of Allegheny and State ofennsylvania, have.v invented a new and useful Im rovement in StartingDevices for Electric Motors, of which the following is a specification.

My invention relates to electric motors, and particularly tosingle-phase induction and similar motors in which auxiliary windings,or other auxiliary means, are employed to effect startin v The object 0%my invention is to provide exceptionallylsim le and effective means forinterrupting the clrcuit of the starting winding of an induction motor,or for otherwise rendering the starting means ineffective, when themotor attains a predetermined speed.

Sin provi ed with auxiliary highresistance starting windings, thecircuits of which are interrupted when the motors attain predeterminedspeeds, the means heretofore employed for this purpose being ,operatedby centrifugal force. The said means have, consequently, beencomplicated and expensive in.

construction, more or less unreliable in operation, and diflicult toadjust, and have embodied switch members carried and actuated by therotatable member of the motor for governing the circuits of theauxiliary windm s. I

llhe present device is actuated when the cross magnetizing flux producedin the primary core of the motor by the reaction of the secondary memberattains a predetermined value, and-is so constructed that the circuitofthe auxiliary winding is governed by parts comprising a single movablemember,

the operation ofwhich is mechanically inde pendent of the rotatablemember of the motor.

Figure l of the accompanying drawing is a view, in end elevation, of amotor that embodies my invention, a portion of the casing being brokenaway for the sake of clearness of illustration. Fig. 2 is a view, inside elevation, of the motor shown in Fig. l, a portion of the casingbeing broken away. Fig. 3 is a simplified diagrammatic view of themagnetizable core member and the winding le-phase induction motors areusually flux produced by the main winding of the motor, and 4c is a'diagrammatic view of-the winding in development.

The motor comprises a stationary primary member 1, and a rotatablesecondary mem-- her 2, the former of which is provided with ductors ofthe auxiliary starting winding and, at its outer end, with alongitudinal recess 6 provided in the outer peripheral surface ofthe'magnetizable core. The object of the slit or' opening 6 is toprovide a path of high reluctance .across one of the poles produced inthe core by the main winding, and for that reason, other means, such asa restriction'of the core at 6, may be employed, if desired, foreffecting this result. Located within the recess 6? and arranged to spanthe opening 6 is an armature 7 that carries a conducting strip 8, thesaid armature normally occupying the position shown to permit the strip8 to engage and connect two terminal blocks 9 and 10, one of which isconnected to a terminal of the auxiliary starting winding 5 and theother of which is connected to. one ofthe motor terminals, as indicatedin Fig. 4;.

W' hen current is first supplied to the motor, the greater portion of ittraverses the main winding 4: and a small portion traverses theauxiliary winding 5 by way of the switch comprising parts 8, 9 and 10.The in the portions of the magnetizable core l adjacent to the slit oropening at 6 is directed asindicated by the arrows 11, there being notendency for the said fiux to traverse the opening 6;: since the latteris disposed in a neutral plane of a pole produced by the main winding.However, as the speed of the motor increases, a flux, that increases invalue with the spe d, is produced in the primary core 3, in a directionindicated by arrows 12, by the reaction of the secondary member of themotor, the said flux crossing the slit or opening 6 and thereby causlnga difference of magnetic potential between the portions of the coreadjacent to the said opening.

At the lower speeds, the cross magnetizing flux, as the flux caused bythe secondary reaction is usually termed, is insuflicient to raise thearmature 7, but when the motor has attained a predetermined speed thesaid flux becomes of such a value as to cause the armature to be raisedand the member 8 to disengage the terminal blocks 9 and 10. The circuitof the starting winding is then interrupted and the motor is thereaftercaused to operate by the main winding alone.

I claim as my invention:

1. In an electric motor, the combination with primary and secondarymembers, and an auxiliary starting winding, of a circuit making andbreaking device for said starting winding, the operation of which isdependent upon the cross magnetizing flux in the primary member.

2. In an electric motor, the combination with primary and secondarymembers, and an auxiliary starting winding, of a circuit opening andclosing device for said starting winding which is electro-magneticallyactu-.

ated to open the circuit by the magnetic reaction of the secondarymember upon the primary member.

3. In an electric motor, the combination with primary and secondarymembers, and an auxiliary starting means, of a governing device for thestarting means, the operation of which is dependent upon the crossmagnetizing flux in the primary member.

l. In an electric motor, the combination with primary and secondarymembers, and an auxiliary starting means, of a governing device for thestarting means, the operation of which is dependent upon the crossmagnetizing flux in the primary member, the said starting means beingrendered ineffective when the cross magnetizing flux attains apredetermined value.

5. In an electric motor, the combination with a magnetizable core, andmain and auxiliary exciting windings therefor, of a nor mally closedswitch in the circuit of the auxiliary winding, the operation of whichis dependent upon the cross magnetizing flux in the said core.

6. In an electric motor, the combination with a magnetizable core, andmain and auxiliary exciting windings therefor, of means dependent inoperation upon the cross magnetizing flux in said core for interruptingthe circuit of the auxiliary winding when the cross magnetizing fluxexceeds a predetermined value.

7. In an electric motor, the combination with a magnetizable core, andmain and auxiliary exciting windings therefor, the said core having aslit or opening at approximately the center of one of the poles producedtherein by the main winding, of a switch in the circuit of the auxiliarywindmg, and an actuating armature therefor that spans the slit inthemagnetizable core.

8. In an electric motor, the combination with a magnetizable core, andmain and auxiliary exciting windings therefor, the said core having aslit through one of the poles produced therein by the main winding, of aswitch in circuit with the auxiliary winding, and an actuating armaturetherefor that spans the slit in the magnetizable core.

9. In an electric motor, the combination with a magnetizable core, andmain and auxiliary exciting windings therefor, the said core beingprovided with a high reluctance path across one of the poles producedtherein by the main winding, of an armature that spans the highreluctance portion of the core, and means operated thereby for governingthe circuit of the auxiliary winding.

In testimony whereof, I have hereunto subicribed my name this 28th dayof August, 190

HAROLD M. SCHEIBE.

Witnesses:

W. J. BRANSON, Bummer HINES.

